68Ga-labelled DOTA-derivatised peptide ligands

Ge-68/Ga-68 generators provide cyclotron-independent access to positron emission tomography (PET) radiopharmaceuticals. We describe a system which allows the safe and efficient handling of Ge-68/Ga-68 generator eluates for labelling of DOTA-derivatised peptide ligands. The system comprises concentration and purification of the Ga-68 eluate as well as labelling and purification steps for peptides, and can be used with different Ge-68/Ga-68 generator types. The suitability and efficiency were tested with two different DOTA-derivatised somatostatin derivatives and a DOTA-derivatised bombesin derivative. Amounts of 10-20 nmol of the peptides were sufficient and resulted in labelling yields of 50% for all peptides. The built-in safety precautions have proven to be appropriate in allowing use of the method for routine clinical applications. The system was set up and operated in a hot lab by personnel with no previous experience in the preparation of PET radiopharmaceuticals.